Bending steel tubing?

1001 Views 20 Replies 5 Participants Last post by hellonearth, Mar 29, 2015

hellonearth

Discussion Starter · Mar 28, 2015

Anyone got any tips besides taking it to someone who knows what they are doing/heat?! Trying to make a custom subframe and well steel is stronger than I so I haven't had much luck with it. I don't want to use a long cheater bar in the holes either because its just going to deform the shit out of them. But if I have to I will or if I have to use heat I will

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NatBrown

· #2 · Mar 28, 2015

Which part are you trying to bend and where in it are you trying to make the bend?

hellonearth

Discussion Starter · #3 · Mar 28, 2015

Sorry that would probably help, I'm just trying to get the two open ends to meet as one in a triangle shape so they can be welded together.

Schooley

· #4 · Mar 28, 2015

Heat is almost a necessity in your case, I would try to use a bar that gets all the way into where you want the bend, so you may have to drill out anything in the end of the tubing.

NatBrown

· #5 · Mar 28, 2015

Man, that's going to be tuff since it's two tubes welded together along their length.

Heres what I will tell you, the bend won't happen along the weld. That weld is most likely going to tear the tubing if you try to make the bend in the welded section.

Can't really tell if there is a reinforcing plate connecting the upper and lower tube under the wiring harness. If there isn't, it may be possible that the bend could happen there. But trying to bend two tubes at a time like that is going to require a lot of force.

A couple to things the might work would be a large thick walled tube slipped over the outside of both tubes and then used to give you more leverage to make the bend. Might have to cut the tabs off the subframe for that to work. A solid bar put inside the tubes would also work. If you can put it 10" or so into the tube it probably wouldn't deform the end of the tube much if at all. Any method like this will be hard to do because it's going to be really hard to secure the bike to keep from just pulling the front end around.

Another thing you could try would be to loop a ratchet strap around the ends of both tubes and use it to squeeze them together as you tighten it. Finishing the bend will be problematic if this works.

Heat will be your friend if you try the first method. Ratchet strap might melt by the time you get enough heat in the tubing. If you apply heat your going to need to get it orange to cherry red to make the bend. The problem with doing this in tubing is that the tube wall tends to want to collapse when it's that hot.

In all honesty, I'd leave it as is but that's just me. If I really wanted to make it the shape your suggesting, I'd probably just cut a pie cut in the tubing where I wanted the bend, then bend it back together and weld the pie cut back together. Wont be a pretty smooth bend but it would get the shape you want. If I really, really, really wanted a smooth round bent shape, I'd just get some tubing and build it from scratch.

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hellonearth

Discussion Starter · #6 · Mar 28, 2015

Thank you both for the help. I'll try and get a piece of tubing to go over both pipes. I'm pretty strong so maybe I can make it work. I tried the ratchet straps and broke two of them :/ but I'll apply heat if worse comes to worse. Seriously thank you both.

hellonearth

Discussion Starter · #7 · Mar 28, 2015

Oh and I'm trying to run a gen4 zx10r race tail that's why I want to shape it in this way. If it turns out to be to much trouble so be it but I at least wanted to try.

hellonearth

Discussion Starter · #8 · Mar 28, 2015

After about 30/minutes of struggle I got about this much with a 8ft cheater bar. Looks like I'm gonna be using heat :/

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hellonearth

Discussion Starter · #9 · Mar 28, 2015

Moar progress? Lol its getting ridiculous.

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Matoo

· #10 · Mar 29, 2015

Umm...you aren't bending it...you are creasing it. That is making it very weak. I would have placed something between them where you wanted it to bend and then heat it big time before applying pressure. Then slow steady pressure. But with the welds in that area, you are pissing into the wind.

Schooley

· #11 · Mar 29, 2015

Looks like you won't be giving any fat chicks any rides :laugh

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messi4

· #12 · Mar 29, 2015

might want to start from scratch.. pre-bend everything and tack it all together to make sure its going to work before welding it up.

I wouldnt trust that crease.. too risky

hellonearth

Discussion Starter · #13 · Mar 29, 2015 (Edited)

Bahah. You guys

.

Thanks for the advice, but the amount of pressure applied vs what i'll be putting on it is enormously different.

And thanks but I'm not stupid. If I had the money for a one off I would of done it. With my budget and my goals of racing. I'll do anything to make.it happen including this. So no offense but fuck your ,"you've weakened it" opinion. If I crash and break it then I'll fix it in the same manor. Is it motogp/professional? Fuck no. But then again neither am I. I make shit work with what I and I Alone have.

hellonearth

Discussion Starter · #14 · Mar 29, 2015

Schooley said:
Looks like you won't be giving any fat chicks any rides :laugh

On a race bike? Nah they can walk :laugh

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Matoo

· #15 · Mar 29, 2015

hellonearth said:
Bahah. You guys .

Thanks for the advice, but the amount of pressure applied vs what i'll be putting on it is enormously different.

And thanks but I'm not stupid. If I had the money for a one off I would of done it. With my budget and my goals of racing. I'll do anything to make.it happen including this. So no offense but fuck your ,"you've weakened it" opinion. If I crash and break it then I'll fix it in the same manor. Is it motogp/professional? Fuck no. But then again neither am I. I make shit work with what I and I Alone have.

You won't have to crash for it to break. Ever fold a piece of paper back and forth before you tear it? You just did that. The force you put into it has nothing to do with it, it will take WAYYY less to fail now. The strength comes from the shape of the tubing and you have now created high stress points. Points that you have made weak in the process of creating it.
I just hope you don't hurt yourself, or more importantly, someone else when it fails.:coocoo

Reactions: 1

hellonearth

Discussion Starter · #16 · Mar 29, 2015

Matoo said:
You won't have to crash for it to break. Ever fold a piece of paper back and forth before you tear it? You just did that. The force you put into it has nothing to do with it, it will take WAYYY less to fail now. The strength comes from the shape of the tubing and you have now created high stress points. Points that you have made weak in the process of creating it.
I just hope you don't hurt yourself, or more importantly, someone else when it fails.:coocoo

Lol Kay. Thanks for the input :laugh

hellonearth

Discussion Starter · #17 · Mar 29, 2015

I had to use 8ft cheater to flex it at all. Im sure your engineering degree will hold strong tho. Even tho I've increased the surface area vs the horz plane. Please tell me moar.

Matoo

· #18 · Mar 29, 2015

Yeah, what do I know.... certified welder and deal with tubular metal for a living.
Don't ask for advise if you don't want the answers

Reactions: 1

hellonearth

Discussion Starter · #19 · Mar 29, 2015

And don't act like your advice is the word of god. It will hold me just fine.

hellonearth

Discussion Starter · #20 · Mar 29, 2015

Matoo said:
Yeah, what do I know.... certified welder and deal with tubular metal for a living.
Don't ask for advise if you don't want the answers

Kool beanz. Im sure you've experimented with every possible outcome of steel :laugh

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